Protractor.



,Y UNITED STATES "PATENT OFFICE.

CHARLES L. KLINE, oF CHICAGO, ILLINOIS.

PRCTBACTCCR.

SPECIFICATION forming part of Letters Patent N. 724,018, dated Marhf31j,g1eos.

Application filed OOtObelj 21, 192. Y

To all 'whom it maycongccrn: 1

' Beit known that I, CHARLES L. KLINE, a 'citizen' of the United States, residing at Chicago, in the county of Cook andvState of Illinois, have invented certain new and useful Improvementsv in. Protractors; and I do de#Y clare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to which it appertainsfto make and use the'same.

\ A f This invention relates'to protractors.

The object is to provide an instrument of this character which is simple of construction, readily adjustable, comparatively inexpensiveof manufacture, and designed to afford superiorfacilities for angle-work.

With this and other objects in view the invention consists of certain novel features of construction,combination, and arrangement of parts, as will be more fully described, and particularly pointedout in the 'appended claims.

In the accompanying drawings, Figure lis a plan view of the obverse side of a protractor embodying my invention. Fig. 2 is an edge j view thereof.- Fig. 3 is a section on the line f 44er Fig. 1.

3 3 of Fig. .1.'V Fig. 4 is a section on the line Fig. 5 is an enlarged detail section on the line 5 5 of Fig. 1. Fig.'6 is a plan View showing the application of the auX- iliary blade, a portion ofthe upper face of the protractor being broken away .to show the pivot and form of the adjacent portion of the main blade.

Referring now more particularly to the drawings, 1 representsl the protractor-blade, provided with a scribing edge2fa right-angular iiange 3 at one end projecting beyond the scribing edge and an ear 4 also extending beyond the scribing edge at a point adjacent to saidA flange. 4The blade is further provided with a slot 5 at a point below the ear 4. and with a rib 6 in longitudinal alinement with the scribing edge 2 andhavinga-n overhanging anged end 7. This; rib bears" senti No. 128,147. gno man.)

forming an interposed recess to receive the blade 1, n`the opposite sides of which the plates are thereby positioned,as clearly shown in Fig. 2. The upper or obverse plate 11 is provided with scale-graduations to coperate with the indicator line or point 8. It will be observed f that byrpivotingthe segment at a certain distance outl from the' scribing edge 2 the scribing edge when the segmentis set at an acute angle will be continuous from the pivot tothe extreme end; also, that byformingthe protraetor-segment with obverse and reverse sides disposed on opposite sides of. theblade, the operator by first using one side of the instrument and then turning it over and using the other side may obtainperfectly-correct reverse angles.

The lower half of the plate 11 of the protractor is formed adjacent to its straight edge with a slot 14 and has connected thereto at one end a spring-detent `15, the tree end of which is provided with a head 16, forming a finger-piece and a'rcatchto engage the slot`5. This head is adapted to move in the slot 5 and is tapered vor Wedge-shaped at its base to tains the head out of engagement with slot 1'5; but when the segment is adj usted to a position at right angles to the blade the slot 14 comes'into registerwith slot, andthe 4operator-by pressing down'on lthe head 16 may forc'ethe lWedgelsha'ped Vportion yot the head through slot V14C and into slot 5, the frictional engagement of the Wedge-shaped'portion with thewallsl of slot`5 serving to 'hold the head secured therein and the segment ixed against movement.V A slight upward pull on the upper portion of the head will, however, disengage the same from the slot 5 and the spring action of the detent will retract the head, to its normal position and release the segment from locking engagement with the blade 1. By the provision of this detent the operator may obtain a quick adjustment vof thensegment to a position at right angles without indetent form a perfect register for such adjustment, and the detent enables the segment to be held against movement in this position until the clamping-screw (hereinafter described) IOO ing-plates 2O 20', disposed on opposite sides of the flange 3, and the flange on the plate 11 is also engaged by the flanged end 7 of therib 6, whereby a guide is formed for the said curved edges of the plates, andthe edge of the plate 1l is prevented from springing out of registering alinement with the rib. The

clamping-plates are providedwith dowel-pins l 21 to fit within an opening 22 in the flange 3 and also with an opening to receive a clamping-screw 23, which also passes through the flange and by `means of which the plates 20- 20 may be drawn together to clamp the flanges and hold the segment against movement or forced apart and disengaged from the flanges to release the segmentA This construction provides a clamp which is effective in action, may be quickly applied and released, and:

when applied holds the segment firmly against lnovement at any desired angle.

In order to enable an extreme obtuse angle to be obtained, I provide an auxiliary blade 24, having a forked end 25 to enter between the plates 1l and 12 and straddle' the pivot 10, whereby the blade may be held in position for use in the manner shown in Fig. i

From the foregoing description, taken in connection with the accompanying drawings, the construction and operation of the invention will be readily understood without requiring a more extended explanation.

Various changes in the form, proportion, and the minor details of construction may be resorted to without departing from the principle or sacriiicing any of the advantages of this invention.

Having thus described lmy invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A protractor comprising a blade, a protractor-segment pivoted thereto and consisting of spaced connected plates disposed on 0pposite sides of the blade, clamps disposed on opposite sides of the blade and adapted to engage the curved edges of the plates, and

means for adjusting said clamps,substantially as described.

2. A protractor comprising a blade having `on opposite sides of the blades, means for spacing and connecting the plates, means pivotally connecting the plates to said pivoting projection, clamps disposed on opposite sides of said llange to bear upon the curved edges of the plates, and means for adjusting said clamps, substantially as described.

'3. A protractor comprising a blade having a flange and a pivoting projection extending beyond its working edge, a protractor-seg ment consisting of a pair of plates disposed on opposite sides of the blades, means for spacingandconnecting the plates, means pivotally -connecting the plates to said pivoting projection, clamps disposed on opposite sides of said flange to bear upon the curved edges of the plates, and means for adjusting said clamps, and a rib upon the blade adjacent said flange and bearing an indicator-point and havin a flanged edge engaging the edge of one of t e protractor-plates, substantially as described.

4. Aprotractor comprising a blade having a flange and a pivoting projection extending 'beyond its working edge, a protractor-segment consisting of a pair of plates disposed on opposite sides of the blades, and each havi-ng a flanged curved edge, means for spacing and connecting the plates, means pivotally connecting the plates to said pivoting projection, clamps disposed on opposite sides of said flange to bear upon the flanged curved edges of the plates,` means for adjusting said clamps, and a rib upon the blade adjacent said flange andrhaving a flanged edge engaging one of the flanged edges of the plates, substantially as described.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

CHARLES L. KLINE.

Witnesses:

FRED. NIEMANN, WM. F. DOERNLAND. 

